The present invention relates generally to devices and methods for suturing body tissue. More particularly, the present invention is useful for performing end-to-side attachments of body ducts, such as in suturing coronary blood vessel grafts.
In many medical procedures today, it is desirable to connect a body duct, such as a hollow organ or blood vessel, to a targeted piece of tissue. In coronary surgery, this type of attachment is commonly referred to as an anastomosis. In certain heart operations where coronary artery bypass graft surgery (xe2x80x9cCABGxe2x80x9d) is performed as shown in FIG. 1A, a graft blood vessel G may be affixed to a port or aperture in an arterial wall of an artery to supply blood downstream of a blockage in another blood vessel V. The proximal end of the blood vessel graft is typically connected to a pressurized arterial blood supply, such as the aorta A, while the distal end is coupled to the vessel lumen downstream of the blockage. The amount of time spent performing these anastomosis procedures to connect blood vessel grafts between blocked arteries and pressurized blood supplies is critical to patient mortality and morbidity. In conventional CABG surgery, three critical determinates that affect the outcome of a bypass surgery are (1) time the patient spends on cardiopulmonary bypass, (2) time the patient spends with a clamped aorta, and (3) the quality of the anastomosis. It is generally understood that the risk of patient morbidity rises significantly after a threshold time of one hour on cardiopulmonary bypass. Continual circulation of blood through the mechanical apparatus of the bypass machine can cause various degradations to the blood. Perhaps the most prevalent complication arising from prolonged cardiac bypass is the high risk of distal thrombosis, which can embolize into the neurovasculature and potentially cause a stroke.
A critical factor in reducing the amount of time a patient spends on bypass is directly related to the time spent anastomosing the blood vessel grafts used during surgery. The average time for suturing one anastomosis is approximately seven to ten minutes. It is believed that an average CABG procedure involves approximately five anastomoses. Therefore, the average time for graft suturing ranges from thirty-five to fifty minutes, which is a significant portion of the sixty-minute threshold for patient morbidity. Patients treated with conventional coronary surgery and placed on cardiopulmonary bypass would benefit from reducing the amount of time spent performing each anastomosis.
In xe2x80x9coff pumpxe2x80x9d procedures where patients are not placed on cardiopulmonary bypass and the heart remains beating, the difficulty of suturing an anastomosis graft on a moving surface of the heart may degrade the quality of such grafts completed on patients. xe2x80x9cOff pumpxe2x80x9d procedures do not use cardiopulmonary bypass pumps or devices and thus reduces the blood damage associated with bypass devices. xe2x80x9cOff pumpxe2x80x9d procedures, however, requires a higher degree of expertise to perform coronary artery bypass grafts on a beating or moving object. An anastomosis differs from straight line suturing in that each suture has a different orientation that is based on its position around the cross-sectional circumference of the blood vessel graft. It can be appreciated that some of the sutures are easily made from on top of the conduit or blood vessel graft, while others are more difficult to complete as they are beneath the conduit. It can be further appreciated that performing such complex suturing procedures on a moving platform, such as the beating heart, further increases the difficulty associated with such suturing procedures. Improperly connecting blood vessel grafts to the patient may present substantial post-operative complications and/or increase operating room time spent correcting the improperly connected graft.
Accordingly, it would be desirable to provide improved devices and methods that simplify anastomosis graft procedures performed on patients, particularly where multiple graft procedures are to be performed. Simplifying the anastomosis procedure would typically reduce the time spent on each graft and thus minimize the time a patient spends on cardiopulmonary bypass. Additionally, it would desirable to provide a device that improves the consistency of the suture pattern created during each anastomosis graft.
The present invention comprises systems, methods, and kits for facilitating the suturing of one body duct to another body duct or tissue surface. The present invention simplifies suture delivery, reducing the amount of time required for performing an anastomosis and facilitating the delivery of suture needles through blood vessels. The present invention may be used in a variety of environments and is applicable to both stopped heart and beating heart procedures. The prevent invention may be used in a minimally invasively environment using percutaneous ports such those developed by Heartport, Inc. of Redwood City, Calif. or retractor systems developed by CardioThoracic Systems of Cupertino, Calif. Of course, the present invention may also be used in an open surgery environment.
The present invention preferably allows the delivery of a plurality of needles through both body ducts in a single continuous motion by the user. Advantageously, this simplified needle/suture delivery reduces the amount of time spent on performing body duct connections such as an anastomosis. In situations where the invention is used with a beating heart, the invention allows for rapid actuation once the device is properly positioned, reducing the likelihood that movement of the beating heart may misposition the device during actuation. The present invention further allows for the simultaneous delivery of a plurality of needles through the body ducts in an evenly-spaced manner which thus improves the quality of the anastomosis by having a consistent suture pattern and a calculated tissue capture. The present invention is also particularly useful when targeting a pressurized blood vessel when it is desirable to maintain hemostasis at the targeted suture site.
In one aspect of the present invention, a device is provided for suturing one end of a first body duct to a hole in the side of a second body duct. When performed during coronary surgery, such connections of the body ducts are known as end-to-side anastomoses. The device according to the present invention includes a structure for holding the end of the first body duct and positioning the end adjacent to the hole in the side of the second body duct. The structure of the device is typically a shaft having a surface adapted to receive the first body duct. The first body duct used during anastomosis is typically some type of tubular graft such as a saphenous vein while the second body duct is the targeted blood vessel. Further examples of first and second body ducts are provided in the detailed description below.
A plurality of needles are arranged on the structure to be advanced along a plurality of paths. FIG. 1B depicts preferred paths according to the present invention. Each needle path first passes radially into and forwardly out of the end of the first body duct and into the hole of the second body duct. The path then everts so that the needles and associated sutures will pass outwardly through tissue peripheral to the hole when the end of the first body duct is on the structure adjacent to the hole in the second body duct. The needles preferably travel along such paths when they are advanced forward. The structure of the device typically includes a plunger which may be translated to advance the needles forward through the first body duct. The plunger may include suture storage area for sutures attached to the needles.
The needle paths of the present invention may be defined in a variety of manners. In one embodiment of the present invention, a plurality of guide channels are provided to define the path of the needles. The channels may be integrally formed in the device structure or they may be individual guide tubes. The guide channels typically have a first portion and a second portion where the first and second portions are separated by a gap which receives the end of the first body duct. The first portion of the guide channel is adapted to be positioned outside the first body duct and has a distal opening positioned to open towards an outer surface of the first body duct when the first body duct is mounted on the structure, between the gap. The second portion of the guide channel is adapted to be positioned in the lumen of the first body duct when the first body duct is mounted on the structure within the gap.
The needles are advanced from the first portion of the guide channel to pass through the body duct wall and into the second portion of the guide channel. The needles are preferably of sufficient length to extend through the guide channels and through the tissue layer of the second body duct. The second guide channel preferably has a J-shaped section to guide the needle along the desired path. The needles passing through the J-shaped section will assume an everted configuration directing the needles toward peripheral tissue around the hole in the second body duct. The guide channel or tube may also have a longitudinal slot extending along a portion of the channel or tube to facilitate removal of the suture once the needle has been removed from the guide channel. To facilitate delivery through the curved portions of the guide channel, the needles used in the guide channels are typically made of materials such as a shape-memory alloy or a superelastic material.
In another embodiment of the suturing device, the present invention uses a plurality of needles having an arcuate profile when unconstrained to define the needle path. The needles are constrained by a tubular constraint on the structure and the needles are movable between a first position and a second position. In the first position, the tubular constraint maintains the needles in a substantially straight configuration. In the second position, the needles are advanced forward and extend beyond the tubular constraint, assuming the arcuate profile. The tubular constraint typically comprises an outer tube and an inner tube. The outer tube has a passage with the inner tube slidably mounted within that passage. As seen in the figures, the tubes are typically coaxially aligned and have a slideable relationship relative to each other. In this embodiment, the needles are fixedly secured to the distal end of the inner tube so that the needles are adapted to penetrate one end of the first body duct when the body duct is mounted within the inner tube. When the needles assumes the arcuate profile, the sharpened distal tips of the needle preferably point in a proximal direction towards tissue peripheral to the hole in the second body duct.
In another aspect of the present invention, a method is provided for suturing one end of a first body duct to a hole in the side of a second body duct. Although not limited in this manner, such suturing is particularly suited for performing an anastomosis graft during coronary surgery. The method involves positioning one end of the first body duct adjacent to the hole in the second body duct. A plurality of needles are advanced, carrying a plurality of sutures along a plurality of paths. Needles following each path first passes radially into and forwardly out of the end of the first body duct and into the hole of the second body duct and then everts to pass outwardly through tissue peripheral to the hole when the end of the first body duct is on the structure adjacent to the hole in the second body duct. A portion of at least one of the sutures is secured outside of the first body duct to a portion of the suture outside of the peripheral tissue surrounding the hole in the second body duct. Typically, the first body duct is mounted against a shaft structure containing the plurality of needles. This may involve placing the body duct over a portion of the shaft structure or placing the body duct within a lumen of the shaft structure.
The method typical involves advancing a plunger or similar device to drive the needles along the desired path. In one embodiment, advancing the needles involves passing the needles through guide channels which define the paths. The guide channels each have a first portion and a second portion, where the first and second portions are separated by a gap which receives the end of the first body duct. Advancing the needle typically comprises passing the needle through the first portion of the guide channel, through the wall of said first body duct, and into the second portion of the guide channel. As the needles are advanced, they will also be everted. The second portion of the guide channel has a curved portion which will bend the needle to have a partially everted configuration. Securing the sutures involves removing the sutures from the guide channels by lifting the sutures out of the channels through a longitudinal slot running along a length of at least one of the guide channels.
In another embodiment, the prevent invention provides another method for everting the needles as they are advanced. The needles used in this method have arcuate profiles when unconstrained. The everting comprises passing the needles forwardly from a tubular constraint so that the needles assume an everted configuration as they are passed forwardly. Typically, the method involves providing a suturing device having two coaxially-mounted tubes where at least one of the needles is made of a shape-memory alloy and is mounted on the inner tube. The needles are extended beyond the outer tube by relative motion between the needle and the outer tube where the needle is extended to the arcuate configuration, preferably where a sharpened tip of the needle points substantially in a proximal direction. It may be necessary to lift the shaft structure in a proximal direction to pull the needles through the peripheral tissue surrounding the hole in the second body duct.
Kits according to the present invention will comprise a graft suturing device which delivers a plurality of needles. The kits will further include instructions for use setting forth a method as described above. Optionally, the kits will further include packaging suitable for containing the graft device and the instructions for use. Exemplary containers include pouches, trays, boxes, tubes, and the like. The instructions for use may be provided on a separate sheet of paper or other medium. Optionally, the instructions may be printed in whole or in part on the packaging. Usually, at least the graft suturing device will be provided in a sterilized condition. Other kit components, such as the graft to be sutured, may also be included.
A further understanding of the nature and advantages of the invention will become apparent by reference to the remaining portions of the specification and drawings.